WO2014140039A1 - Chirurgischer gleichstromschneider - Google Patents

Chirurgischer gleichstromschneider Download PDF

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Publication number
WO2014140039A1
WO2014140039A1 PCT/EP2014/054740 EP2014054740W WO2014140039A1 WO 2014140039 A1 WO2014140039 A1 WO 2014140039A1 EP 2014054740 W EP2014054740 W EP 2014054740W WO 2014140039 A1 WO2014140039 A1 WO 2014140039A1
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WO
WIPO (PCT)
Prior art keywords
instrument
implant
electrodes
cutting
contact
Prior art date
Application number
PCT/EP2014/054740
Other languages
German (de)
English (en)
French (fr)
Inventor
Sebastian Schostek
Chi-Nghia Ho
Michael Melbert
Marc O. Schurr
Thomas Gottwald
Original Assignee
Ovesco Endoscopy Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ovesco Endoscopy Ag filed Critical Ovesco Endoscopy Ag
Priority to JP2015562097A priority Critical patent/JP6194026B2/ja
Priority to EP14709301.7A priority patent/EP2967712B1/de
Priority to US14/774,694 priority patent/US10881454B2/en
Priority to ES14709301.7T priority patent/ES2628101T3/es
Publication of WO2014140039A1 publication Critical patent/WO2014140039A1/de

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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B18/1442Probes having pivoting end effectors, e.g. forceps
    • A61B18/1445Probes having pivoting end effectors, e.g. forceps at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
    • A61B18/1447Probes having pivoting end effectors, e.g. forceps at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod wherein sliding surfaces cause opening/closing of the end effectors
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B18/1442Probes having pivoting end effectors, e.g. forceps
    • A61B18/1445Probes having pivoting end effectors, e.g. forceps at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00642Sensing and controlling the application of energy with feedback, i.e. closed loop control
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00666Sensing and controlling the application of energy using a threshold value
    • A61B2018/00672Sensing and controlling the application of energy using a threshold value lower
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00666Sensing and controlling the application of energy using a threshold value
    • A61B2018/00678Sensing and controlling the application of energy using a threshold value upper
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00696Controlled or regulated parameters
    • A61B2018/00702Power or energy
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00696Controlled or regulated parameters
    • A61B2018/00714Temperature
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00696Controlled or regulated parameters
    • A61B2018/0072Current
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00696Controlled or regulated parameters
    • A61B2018/00761Duration
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00696Controlled or regulated parameters
    • A61B2018/00767Voltage
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636Sensing and controlling the application of energy
    • A61B2018/00773Sensed parameters
    • A61B2018/00875Resistance or impedance
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/1206Generators therefor
    • A61B2018/1266Generators therefor with DC current output
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B2018/1405Electrodes having a specific shape
    • A61B2018/142Electrodes having a specific shape at least partly surrounding the target, e.g. concave, curved or in the form of a cave
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/06Measuring instruments not otherwise provided for
    • A61B2090/064Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension
    • A61B2090/065Measuring instruments not otherwise provided for for measuring force, pressure or mechanical tension for measuring contact or contact pressure
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02Prostheses implantable into the body
    • A61F2/04Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2002/044Oesophagi or esophagi or gullets
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/95Instruments specially adapted for placement or removal of stents or stent-grafts
    • A61F2002/9528Instruments specially adapted for placement or removal of stents or stent-grafts for retrieval of stents

Definitions

  • the present invention relates to a surgical cutting device for the
  • Fragment thin-walled and / or wire-shaped metal implants with direct current are provided.
  • stents are often used for the therapy of constrictions, perforations and fistulas, in particular in the digestive tract of a patient.
  • Such stents are tubular braids which, when compressed to a minimum size or folded, are guided via an inserted endoscope or trocar to a selected destination and then applied.
  • the respective stent unfolds elastically to its full size and so can support the organ wall or cover existing fistulas or perforations and seal.
  • stents designed to cover organ wall perforations or fistulas often have a silicone membrane between their wire mesh. This prevents u. a. Digestive juices and / or bacteria enter the perforation or fistula and there lead to inflammation or at least the
  • Stents of this type however, especially if they must remain in the body over a longer period of time, grow into the organ tissue, so that they must be pulled out of the tissue partly by force, which naturally can cause complications such. the re-generation of a lesion and in the worst case a perforation.
  • implants to be removed subsequently include not only braided stents as described above but also tissue clips for temporary use Anchoring of various measuring probes in a hollow organ or for the selective closing of organ perforations, as they can occur, for example, when removing polyps digestive tract of a patient. Also exist
  • hook-shaped tissue anchors / expansion anchors whose tentacles drill into an organ tissue and can then grow in after a short time.
  • implants In order to safely explore implants of this type for the patient, there is a fundamental need for an instrument which makes the implant in question easier to remove by cutting (cutting) of the implant material and thus prevents possible complications.
  • implants usually consist of metal or a metallic alloy, which are usually designed to withstand special loads, mechanical cutting tools such as endoscopic scissors, RF loops, APC, etc. actually unusable, at least however unsuitable.
  • the bipolar instrument disclosed herein is for endoscopically controlled reduction and / or fragmentation of stents present in the gastrointestinal tract, tracheobronchial system, or other hollow organs and has at its distal end
  • Instrument head two firmly interconnected, i. relative to each other
  • immobile instrument industries which define between them in the direction of a proximally V-shaped tapered gap.
  • an electrode which is mounted to the instrument head or to the instrument industries in an electrically insulating manner.
  • the braided wire enters the V-shaped gap between the instrument branches until it comes to lie at the gap-most end. In this position has the Braiding then an optimal distance from the electrode, which forms an arc between the electrode and the braid wire, which brings the braid wire to melt when an HF current is applied.
  • Another basic problem is the heat input into the stent material. If, for example, electric current is introduced directly into the stent material, it heats up, which can lead to damage to the surrounding patient tissue. For this reason, this prior art also provides a protective device which spaces the electrodes / stent wire from the patient tissue. Such a protective device makes the instrument more expensive and also makes it more unwieldy.
  • a DC-based surgical implant cutter which can be introduced endoscopically or in the manner of a catheter into the patient, and whose cutting ability can be kept stable for different implants.
  • a preferred aim of the present invention is also to improve the surgical
  • Implant cutter as cost-effectively as possible without major design effort.
  • the surgical implant cutter according to the invention should preferably help avoid or at least indicate application errors.
  • Embodiments are the subject of the dependent claims.
  • the invention is based on the following basic considerations:
  • the heat input should be as low as possible and still lead to a melting of the stent material.
  • This can be achieved by keeping a contact / contact area between electrode and stent material as small as possible (preferably point- or line-shaped) in order to obtain a high current density (with direct application of a direct current) in the contact area / junction. That the active contact / contact surface on at least one electrode is designed so that the highest current density along the entire electrical current path is achieved here. This is then sufficient to partially melt the stent material (only) at the contact point without the entire stent heating up excessively.
  • the introduction of heat should be effected by direct application of a direct electrical current by applying the electric current
  • each resulting DC package causes a heat energy in the stent material, but the heat dissipation in the surrounding tissue due to the inevitably short pulse duration comparatively (compared to non-pulsed current application) is low.
  • the electrodes of the bipolar instrument should additionally or alternatively be arranged on the instrument tip such that the instrument itself develops a kind of protective effect without having to arrange a special protective device according to the prior art. For this has the
  • a measuring device which preferably has the electric
  • the electrode material also has a specific material property which counteracts or prevents / restricts thermal material wear.
  • the term "resistance - adjusted specific melting energy" as the specific material property is introduced in this application. This is essentially calculated from material-specific constants such as the specific one
  • Heat capacity c the mass density p, the melting temperature T s and the electrical resistivity r. This material property allows a direct comparison of different materials as to how quickly these materials are melted for a given electrical current flow (the lower the resistance-adjusted specific melting energy, the faster a material is melted for a given current flow).
  • the value of the resistance-adjusted specific melting energy for the electrode material should, according to the invention, be higher than that of the stent material, preferably by at least a factor of 2.
  • One aspect of the present invention consists in the fact that in the event that the opposed, a cutting gap forming instrument branches are each equipped with an electrode or each forming an electrode, the implant material to be fragmented as it is inserted into the cutting gap direct electrical and physical contact receives with the electrodes (ie this short-circuits), creating a direct current (short-circuit current) through the electrodes (ie this short-circuits), creating a direct current (short-circuit current) through the
  • Implant material is passed (without arcing), which leads to its partial heating. That is, the implant material located between the electrodes is heated strongly at a selected current and starts partially (between the Electrodes) and melt / drain. If the instrument head is moved further into the implant material, if necessary, the two instrument branches additionally cause a division of the molten implant material at a low mechanical feed force, which may be transmitted via the implant
  • Instrument shaft for example, within the insertion aid (endoscope, trocar, etc.) can be applied easily.
  • the present invention also differs fundamentally from known TFT - instruments of Bipolarbauart (Tissue Fusion Instruments), in which, although also two instrument industries with
  • Electrodes for tissue division or tissue welding are equipped, but the electrodes are on the one hand acted upon by RF power and on the other hand, the instrument industries must be movable relative to each other to clamp the patient tissue to be treated between them with a certain contact pressure.
  • the metallic implant material according to the invention by the DC short circuit at least as far
  • a particularly high current density is formed in the relevant contact connection between the electrodes or at least one of the electrodes and the implant as a result of a locally reduced current path occurring there. That The contact area and thus the current path between the at least one electrode and the implant must be so small that the high current density occurring there leads to a melting of the implant material (only) between the electrodes. This is accomplished by having the at least one electrode (or the electrodes on both branches) provided for contact engagement with the implant, with respect to a plane (i.e.
  • Electrode on a plane surface has a (substantially one-dimensional) contact line preferably in the electrode longitudinal direction or a (substantially
  • the at least one electrode is curved longitudinally convexly or channel-shaped on its side facing the other electrode. If such a channel is placed on a plane on its outer circumference, this results in unequivocal (essentially one-dimensional) line contact or even point contact. It is also possible to form the at least one electrode with a narrow longitudinal bead, which forms a (sharp-edged) contact strip protruding from the other electrode on the electrode. Finally, it is also conceivable to design the at least one electrode in the shape of a spherical cap so as to realize / approximate a substantially point contact.
  • DC pulses of high current (of up to 200 amps, preferably between 100 - 150 A) control technology to be acted upon.
  • the metal is thereby fused and cut between the electrodes without excessively heating the implant material in the vicinity of the cutting gap.
  • the reason for this, as has already been indicated above, is that the heat spillage effect from the stent into the surrounding tissue can be reduced by current pulsation.
  • the voltage can be well below a limit of 48 volts for a low voltage (preferably between 20-40 V), which is completely safe for the patient.
  • the implant material heats up very hot at these very small-area contact points and can therefore be melted quickly before the implant material further away is warmed up.
  • the electrodes are made of a heat-resistant material such as tungsten or consist of a low-alloy steel.
  • the two electrodes and / or the two instrument branches may be substantially V-shaped with each other, so that the welding / cutting gap forming therebetween narrows continuously proximally in a linear or convex curve shape.
  • a kind of biasing means may be provided on the instrument tip, which biases the electrodes and / or the instrument industries with a certain biasing force against each other, so that an inserted therebetween
  • Implant material is squeezed / squeezed on both sides almost automatically.
  • an electrical / electronic contact quality detection (measuring device) is optionally provided, which executes a test sequence (automatically always or selectively) upon actuation of the instrument and (temporally) before the resulting electrode application with the DC direct current / cutting current.
  • a test sequence automatically always or selectively upon actuation of the instrument and (temporally) before the resulting electrode application with the DC direct current / cutting current.
  • the height of the DC line current to be supplied can be adjusted on the basis of the determination result in such a way that melting of the implant material is ensured.
  • Cutting electrodes would exceed so as to prevent damage or rapid wear of the cutting instrument.
  • stent implants are made of a stainless steel or a titanium alloy
  • Fig. 1 shows the conceptual arrangement of a DC powered
  • Bipolar type surgical implant cutting instrument according to a
  • FIG. 2 shows the conceptual design of two rigid instrument branches on a distal instrument head
  • 3a and 3b show the conceptual design of two elastic or elastically mounted instrument branches on the distal instrument head in an operating position extended and retracted from an insertion aid
  • 4a and 4b show the conceptual design of two articulated instrument branches on the distal instrument head with flared and
  • FIG. 5 shows the conceptual design of two instrument branches on the distal instrument head in contact engagement (short-circuit engagement) with an electrically conductive implant
  • FIG. 6 shows the gripping or contact-engagement principle between the cutting instrument according to the invention and the electrically conductive implant
  • Fig. 7 shows a comparison diagram between the resistance-adjusted
  • FIG. 8 shows a resistance circuit diagram of the instrument-implant current path for a test sequence of an electrical / electronic contact quality identifier of the instrument control
  • FIG. 9 shows a resistance circuit diagram of the instrument-implant-current path for a power current application (cutting sequence) of the instrument control
  • 10a to 10e show a preferred embodiment for the construction of the instrument tip and / or the instrument branches / electrodes
  • FIG. 11 shows the basic principle of an electrical current path through a metallic implant to which two electrodes are applied punctiformly in opposition
  • FIG. 12 shows the electrical current path according to FIG. 11, with allocation of the expected current densities in individual path sections
  • FIG. 13 shows the electrical current path according to FIG. 11 and the thermal current path
  • Fig. 14 shows a table of energy absorption characteristics
  • the surgical implant - cutting instrument of the bipolar type shown schematically in FIG. 1 has a distal instrument head or an instrument tip 1 with (at least) two instrument branches 2, which between them a in
  • Instrument head 1 is mounted on a distal end of a preferably flexurally flexible (or rigid), at least 2-pin instrument shaft 6, which in turn is connected to a controlled / regulated or controllable DC generator 8.
  • the DC generator 8 supplies a direct current from
  • Instrumenten 2 forming gap substantially a proximally tapered V-shape.
  • Instrument head 1 have such an outer diameter (for example, max 6mm) that allows the surgical instrument to be inserted into the (standardized) working channel of a per se known endoscope, trocar, or similar insertion aid.
  • the instrument shaft and instrument head can be designed and dimensioned so that it can be inserted into a patient's hollow organ in the manner of a catheter (without insertion aid).
  • Fig. 2 shows in enlargement a variant of an inventive
  • the instrument industries 2 are firmly connected to the instrument head 1 and also rigid.
  • electrically conductive electrodes 10 are arranged, which are connected via two current conductors (not shown) within the instrument shaft 6 to the DC generator 8.
  • the branches 2 can themselves form the electrodes 10, for which, however, they must be fixed electrically insulated on the instrument head 1.
  • the instrument industries 2 but also with external electrodes 10th
  • the branches 2 and / or the electrodes 10 are made of a flexurally flexible, preferably elastic material or the
  • Electrodes 10 are resiliently mounted on the respective instrument industries 2, such that they can be elastically pressed into the branches 2 by increasing the gap width.
  • Outer sleeve 12 is provided which is axially movable relative to the instrument.
  • This sleeve 12 may be a separate component or the insertion aid itself.
  • the instrument is shown in a position in which the instrument head 1, but at least the instrument industries 2 project axially from the sleeve 12 and thereby radially
  • the instrument head 1 and the instrument industries 2 is retracted or advanced into the sleeve 12, whereby the instrument industries 2 are compressed against their inherent elasticity by narrowing the cutting gap 4.
  • the sleeve 12 may be formed at its distal end with an inner ring or bead 14 which is in sliding engagement with the instrument head 1 and the instrument industries 2, respectively
  • a third variant of a sector construction is shown.
  • the branches 2 per se are preferably rigid, but pivotable on
  • Instrument head 1 (scissor-like) stored. Furthermore, an actuation or
  • FIG. 5 the branches 2 are shown in a maximum gap width position
  • FIG. 6 shows the instrument with instrument branches 2 which are folded together by means of the adjusting device in order to define a minimum gap width.
  • FIG. 7 shows the functional principle of the bipolar current DC-driven implant cutting instrument according to the invention.
  • the instrument industries 2 are basically spaced or spaced such that the longitudinally forming between cutting gap 4 a
  • Slit width which is an insertion of an implant or implant portion 18th
  • the instrument industries 2 are preferably rounded in a banana-shaped / convex manner, at least in the region of their distal (free) end sections, in order to form a convex longitudinal curve at least along the sector sides facing one another.
  • the cutting gap 4 does not taper
  • the implant material comes usually at the distal end portion of the instrument industries 2 with the respective electrodes 10 in the plant and closes this briefly, which due to the applied power current between the
  • Electrode 10 located implant material is heated and melted.
  • the electrodes 10 preferably also dividing the melted implant material. Accordingly, the following are, among others, the following for the described dicing process
  • the electrodes 10 or the instrument branches 2 should preferably have a shape which favors the dicing process
  • the contact resistance between the electrodes 10 and the implant 18 should be as high as possible in order to melt the implant material securely in the contact area (i.e., from outside to inside), while leaving further outlying implant areas as unheated as possible, and
  • the energy input into the implant material should be done so that a
  • the instrument industries 2 and / or at least the electrodes 10 according to a preferred embodiment of the invention have a kind of blade shape with a narrow (sharp) longitudinal edge on each of them
  • the instrument industry 2 is made of a refractory material, preferably tungsten or a low alloy steel.
  • Each sector 2 is formed at its proximal end portion into a kind of hollow plug pin 2a, which, according to FIG. 10e, is inserted in a corresponding receiving socket.
  • Recording sleeve 1 a is inserted on the side of the instrument head 1. Accordingly, two receiving sleeves 1 a are provided for the two sectors 2, which are shown in FIG. 10e are separated by an insulating / diastank 1 b of the instrument head 1 from each other.
  • each branch 2 is formed into a blade shape
  • the blade shape can also be designed such that two (longitudinally) longitudinal sections which are at an obtuse angle to one another are provided, whereby the banana shape is approximated while forming a singular bend. In this way arises at the one
  • each industry 2 Longitudinal side of each industry 2 a narrow (sharp) longitudinal edge / cutting edge 2e, which extends arcuately in the sector longitudinal direction (corresponds to the instrument longitudinal direction).
  • Conductor bundles 6a, 6b are also inserted into the receiving sleeves 1 a and crimped. In this way, each instrument sector 2 or electrode 10 receives electrical contact with a respective conductor bundle 6a, 6b, which in turn to the
  • Each sector 2 forms the one cutting edge 2e, which also defines the line of contact with the implant 18 at the same time, and which thus has a high level of accuracy
  • the cutting edge 2e is preferably used for mechanically dividing the electrical
  • the surgical instrument has a contact quality detection function, such as
  • Fig. 6 the contact grip between the instrument and implant is shown functionally. Ideally, an electric current is conducted via the copper lines 6a, 6b in the instrument shaft 6 to the instrument branches 2 and from there via the point or line contact into the implant section between the branches. As stated above, this achieves a high contact resistance.
  • the implant 18 is not clamped exactly between the contact edges 2e of the instrument branches 2 or electrodes but rests on the electrode of each branch 2 over a large area.
  • the contact resistance between the electrode and the implant would be significantly reduced (current density decreases), so that much more current would have to be conducted in the conductors 6a, 6b in order to achieve a melting of the implant material. This should be avoided in order to prevent the entire implant from heating up.
  • Implant cutting instrument shown.
  • the term "resistance-adjusted specific melting energy" e should be introduced, as indicated in Figure 14 for some selected materials.
  • This measure describes how easily a specific volume (eg 1 mm 3 ) of a conductive material (eg a certain metal) can be melted by a current flow. This measure is calculated according to the following formula:
  • the resistance-adjusted specific melting energy e for these materials is approximately (indicated in 10 15 J m "4 ⁇ " 1 ):
  • the materials are selected so that the resistivity-adjusted specific
  • Melting energy of the materials that are not to be melted is at least twice the resistance-adjusted specific melting energy of those materials
  • the invention to control the current density in such a way that the current density in the target metal to be melted is higher than in the lines and electrodes of the instrument.
  • This is achieved by the inventive design of the electrodes, whereby a point or line-shaped contact surface between the electrode and the metal to be cut is produced, which leads to a high current density.
  • the melting of the target material in comparison to the electrode and conductor material is additional
  • the contact quality between the electrode and the metal to be melted depends strongly on the respective gripping situation.
  • An optimal contact quality is favored by the inventive design of the electrodes.
  • it makes sense to carry out an electrical check of the contact quality according to the present invention.
  • the invention provides for the execution of a test sequence which is executed automatically with each new intervention either automatically or on manual command and which is shown schematically in FIG.
  • the line path is composed of the conductor bundles 6a, 6b in the instrument shaft 6, the branches 2, the contact points and the
  • the contact quality detection function is able to give a warning signal for a faulty grip position and / or the supply of a Blocking current and / or to correct the height of the cutting current below the load limit of the conductor bundles 6a, 6b.
  • the cutting / power current itself can be used for test purposes, in which case the cutting current may be applied for only a short time in order to keep the energy input into the implant smaller than that Energy input that would be required for a melting of the implant material.
  • the crystal lattice of a metal has a characteristic thermal energy, which manifests itself in vibrations of the atoms of the lattice. Thermal energy is thus a kinetic energy.
  • the thermal energy of a substance depends on the temperature T, the mass m and a material constant c (specific heat capacity) and can be expressed by the following formula: Electrical DC current flowing through a metal grid causes excitation of the lattice atoms due to collisions between the flowing charge carriers and the lattice atoms, thus increasing their kinetic energy and consequently increasing the thermal energy (heating).
  • the electrical energy of a DC pulse depends on the electrical power P and the pulse duration At:
  • the electrical energy When flowing through a piece of metal, the electrical energy is completely converted into thermal energy, which leads to a thermal energy difference between before (tO) and after (t1). During the duration of the pulse, the
  • the difference in thermal energy between before (t0) and after (t1) can be described as follows:
  • the temperature increase ⁇ can then be calculated as follows:
  • the bipolar cutting instrument produces the strongest possible local heating of a gripped piece of metal (with the target point of local melting) with the lowest possible entry of electrical energy.
  • the melting of a volume element by direct electrical current according to FIG. 13 can be calculated as follows:
  • the thermal energy E th which is necessary to melt a volume element according to FIG. 11 of a material, is dependent on the initial temperature T 0 of FIG
  • unalloyed steel is particularly well suited as an electrode material for cutting nickel-titanium, since this measure (the specific melt energy adjusted by the resistance factor) for unalloyed steel is significantly higher at 39 than for nickel-titanium at 4.86 (last column in Fig. 14). In other words, if both materials with
  • Bipolar type implant cutting instrument disclosed with an instrument head located at the distal end of an instrument shaft for minimally invasive insertion of the instrument into a patient's body, with at least two opposed instrument sections preferably of the linear type arranged on the instrument head defining therebetween a cutting gap for receiving an electrically conductive implant therebetween or implant section.
  • electrodes are formed on their mutually facing longitudinal sides of the industry or are each equipped with at least one electrode, which in turn are each formed at their mutually facing longitudinal sides to a cutting edge, to a quasi-line or punctiform physical contact engagement with the electrically conductive implant or implant section for an electrical Shorting the opposite electrodes cause.
  • Target metal of the implant is selectively melted, i. Although the DC current, the stent material, but not the lead or electrode material of
  • contact quality is understood to mean the framework conditions set for current density and current path length which result when the implant material is contacted with the instrument. Influencing factors can be, for example, the specific shape of the gripped / contacted implant section. If the gripped / contacted implant section between the electrodes is thin and flat, the result is a low current density; if it is rather narrow, a high current density results. The concrete contacting situation can be individually very different, resulting in different contact qualities. To one
  • the contact quality can be carried out via a resistance measurement.
  • the current path can be described in accordance with FIG. 7 via an equivalent circuit diagram with the following ohmic resistors arranged in series:
  • the contact quality is determined according to the principle of four-wire measurement. This has application before the actual cutting process to determine suitable cutting parameters (current, pulse duration and shape), as well as during the cutting process
  • Milliampere range (e.g., 20 mA). In addition to the determination of the contact quality, it is thus also possible to determine whether an electrically conductive contact has actually been produced.
  • the contact quality determination is before the cutting process (preferably when a stable electrical contact detected was) sent a test pulse through the implant material to be cut, which leads to a warming but not to melting. Heating leads to an increase in the specific resistance of the material and consequently to an increase in the voltage UT between the electrodes, which is determined according to the principle of the four-wire method.
  • this pulse it is possible by means of the increase curve of the electrical resistance between the electrode (corresponding to the resistances REI, RKI, RM, RK2 and RE2 in the equivalent circuit diagram) to derive a prognosis of the energy input required for the melting. This can serve as the basis for setting the cutting parameters.
  • monitoring the voltage UT between the electrodes allows the cutting process to be monitored, with the aim of adjusting the cutting parameters as needed so that e.g. a foreseeable too low set parameter is corrected.
  • the voltages ULI and Ui_2 are determined. This is done both with the test current before the cutting process and with the power current during the cutting process. Since the ohmic resistance of the conductor material changes with temperature, the measurement of the voltage drop at a known current of the ohmic resistance and thus the temperature can be determined. This is particularly useful to detect overheating of the instrument shaft and to avoid by appropriate adjustment of the cutting parameters or termination of the cutting process.
  • the temperature coefficient of various conductive materials is shown in FIG.
  • test current is preferably many times smaller than the power current, it is expedient to be able to selectively amplify the measurement of the voltages UT, ULI and UL2 electronically.
  • a simplified corresponding circuit is shown in Fig. 9.

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  • Health & Medical Sciences (AREA)
  • Surgery (AREA)
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  • Life Sciences & Earth Sciences (AREA)
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  • Otolaryngology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
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  • Heart & Thoracic Surgery (AREA)
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PCT/EP2014/054740 2013-03-11 2014-03-11 Chirurgischer gleichstromschneider WO2014140039A1 (de)

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JP2015562097A JP6194026B2 (ja) 2013-03-11 2014-03-11 外科用の直流電流カッター
EP14709301.7A EP2967712B1 (de) 2013-03-11 2014-03-11 Chirurgischer gleichstromschneider
US14/774,694 US10881454B2 (en) 2013-03-11 2014-03-11 Surgical cutter operated with direct current
ES14709301.7T ES2628101T3 (es) 2013-03-11 2014-03-11 Cortadora quirúrgica de corriente continua

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US11350977B2 (en) 2017-03-08 2022-06-07 Memic Innovative Surgery Ltd. Modular electrosurgical device
DE202018101753U1 (de) * 2018-03-28 2018-05-08 Tuebingen Scientific Medical Gmbh Elektroden-Applikationsinstrument
USD888950S1 (en) * 2018-10-10 2020-06-30 Bolder Surgical, Llc Yoke assembly for a surgical instrument
CN112168343B (zh) * 2020-10-09 2023-05-16 杭州埃杜医疗科技有限公司 一次性射频等离子手术电极
US20220151653A1 (en) * 2020-10-28 2022-05-19 United States Endoscopy Group, Inc. Cap for endoscope

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US20160022356A1 (en) 2016-01-28
JP6194026B2 (ja) 2017-09-06
JP2016509908A (ja) 2016-04-04
EP2967712A1 (de) 2016-01-20
US10881454B2 (en) 2021-01-05
EP2967712B1 (de) 2017-03-08
ES2628101T3 (es) 2017-08-01

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